Underachievers are as much a part of football and the NFL as sacks, blitzes and touchdowns.
Almost halfway through the 2011 seasons, Chris Johnson of the Tennessee Titan stands out as one of the least productive should-be-productive players in the league.
But he's far from alone. On both sides of the ball, there are players who aren't measuring up to expectations. Here are some of our—dare we say it?—favorites.